Field
Exemplary embodiments of the present disclosure relate to a rotor assembly, and more particularly, a rotor assembly in which a structure of cooling fluid inflow, the shape of a coil turn, and a structure of supporting the coil turn are improved.
Description of the Related Art
Generally, a generator is an apparatus which converts mechanical energy into electric energy using electromagnetic induction, and which uses the principle in which electric power is generated when a conductor rotates in a magnetic field. Such a generator uses hydrogen gas and water as a cooling medium, and has a hermetically sealed structure to prevent penetration of dust or moisture and leakage of hydrogen gas.
For ventilation in the generator, a closed circulation system using a fan installed on a shaft of a rotor is employed, and a cooler for cooling hydrogen gas is installed in the generator. Furthermore, a stator houses the rotor therein, and includes a coil, a stator core around which a coil is wound, and a frame which supports them.
When the rotor rotates, current flowing through the coil generates heat. If heat generated from the coil of the rotor is not effectively dissipated, it causes deterioration in performance of the generator.
To overcome this problem, a rotor and a rotating electric machine having a structure for cooling the rotor were proposed in Korean Patent Unexamined Publication No. 2010-0120267.
However, such a conventional rotor is problematic in that because cooling fluid is drawn into space between several structures including a centering ring for supporting a rotor coil, use of only an inlet flow by a pumping head and a fan makes it difficult to efficiently cool the rotor coil.
The conventional cooling structure is a structure in which cooling of a conductor assembled in a rotor body depends on only cooling fluid which is drawn into a sub-slot.
Particularly, because a coil turn which is an assembly of conductors is configured to come into close contact with a spindle of the rotor, there is no space between coil turns, and thus the only way of cooling the coil turns has been to pass cooling fluid through vent holes formed in the coil turns. Accordingly, there is a problem in that it is difficult to efficiently cool the coil turns.